Whereas zero-point fluctuations occur at temperatures right down to absolute zero, an electromagnetic field also experiences an increasing number of thermal fluctuations at higher temperatures. In 1955 the Russian physicist Evgeny Lifshitz predicted that these fluctuations should have a similar effect on radiation pressure, leading to a thermal Casimir force.

Now at Yale University, Lamoreaux has teamed up with Alexander Sushkov and colleagues to measure the thermal Casimir force for the first time. Instead of using two parallel plates, the team looked for the force between a gold-coated plate and a sphere. This is the favoured method of measuring the Casimir force because aligning a sphere and plate is much easier than having to precisely line up two parallel plates.

A wonderful accomplishment!

Zz.

[1] A. O. Sushkov et al., "Observation of the thermal Casimir force", Nature Physics doi:10.1038/nphys1909. (full citation will be included once it is available)